Spinner spreaders for particulate material (particles) are well known in the art, including for agricultural application, lawn care and road maintenance application. Typically, such spreaders are mounted onto areas of machines, such as a truck body, truck chassis, trailer, or slid into a truck's dump body. The system typically includes a particulate material storage bin(s), a conveyor system(s) and rotating spinner disk(s). The conveyor transfers material from the storage bin(s) to the spinner(s). The spinner(s) broadcast the material across a field, lawn or road (broadcast area). Oftentimes a single spinner, or a pair of laterally spaced spinners, are provided, with a material divider plate positioned above the spinner(s) to direct the material from the discharge end of the conveyor(s) onto the spinner(s). A wide range of spinner diameters are in use with a general understanding that the amount of material to be spread and the size of the broadcast area are proportional to the diameter of the spinners.
In operation, the spinner spreader distributes particles by accelerating them with a centrifugal force imparted by the rotating spinning disk(s). However, as particles leave the disk, they are subjected to gravity and drag forces that typically effect their trajectory and ultimate deposition point. Particles with differing sizes, shapes, masses and/or densities will typically travel different distances before coming to rest on the ground. As a result, a disproportionate distribution of particles may occur, which may cause, for example, an undesirable stratification or layering of deposited material at outer edges of the broadcast area.
Disproportionate distribution is not typically of too much concern behind the machine as forward motion of the machine will generally equalize the overall distribution. However, disproportionate distribution on the swath edges, or sides of the distribution area, will oftentimes remain. As a result, an undesirable streaking effect may occur after the machine passes. Consequently, what is needed is an improved system in which particulate material may be evenly distributed without one or more of the foregoing disadvantages.